Bonnie Liltz, the Schaumburg mother convicted of killing her disabled daughter, took her own life Saturday according to her attorney, Thomas Glasgow.

Glasgow said Liltz killed herself Saturday. Schaumburg police said Liltz was found dead in her residence with no evidence of foul play.

Last Tuesday, a judge ordered Liltz to return to prison to finish her four-year sentence for involuntary manslaughter. Liltz was due back in jail Monday after she was convicted in the death of her profoundly disabled daughter.

Liltz, 57, told her mother Saturday she was going to a movie and lunch with a friend. Instead she wrote out suicide notes to family and friends and swallowed an overdose of pills.

Bonnie Liltz knew when she left the courthouse Tuesday she was going to have to go back to prison, where she believed she would die from a lack of proper medical care for a wide range of health problems.

Rather than suffer that fate, her family believes she took her own life, as she told them in a suicide note.

"She said she loved us very much and that she's sorry, that she just could not go back to that place," said Sue Liltz, Bonnie's sister.

Liltz served about three months of a four-year sentence for involuntary manslaughter before a judge set her free on bond during her appeal.

She was convicted for the 2015 death of her profoundly disabled daughter Courtney. Fearing her own death was imminent Liltz gave herself and Courtney a lethal dose of pills. Courtney died but Liltz survived.

"All she ever wanted was to be with her Courtney. She was such, such a good mother," said Gladys Liltz, Bonnie's mother.

When ABC7 spoke to Bonnie Liltz last month, she said still thought about Courtney every day.

"Did I do the right thing, but then I think, she's in a better place," she said in an interview on October 16, 2017, shortly after the Illinois Supreme Court denied her appeal.

Her family believes that the denied appeal sealed her fate.

"Illinois has abolished the death penalty, but she would have died in there. She could not have survived and they didn't care," said her sister, Sue.